In order to evaluate right ventricular function in septic shock, radionuclide-determined right ventricular ejection fractions with simultaneous hemodynamic right ventricular ejection fractions with simultaneous hemodynamics are determined. The initial step in this project has been to evaluate a variety of techniques for determining right ventricular ejection fraction for inter- and intra- observer reproducibility. While first pass techniques have been recommended because there is no overlap activity with the left ventricle, an equilibrium technique using the El Scint collection and analysis programs has been shown to give better inter- and intra- observer reproducibility because the tricuspid and pulmonic valve planes are more readily identified. Using this technique to evaluate right ventricular function in patients with septic shock, it was found that in most patients with septic shock, the changes in right ventricular function over 1-2 weeks parallel the changes in left ventricular function. Further understanding of the pathophysiology of septic shock and the effects on the myocardium should lead to improvement in the treatment of this highly lethal disease.